Locking of retractable type fall arresters--test method and stand.

Retractable type fall arresters are very effective personal equipment protecting against falls from a height. These devices are used under different atmospheric conditions and in the presence of various types of industrial pollution. For this reason appropriate locking after conditioning simulating extreme conditions of a worksite is one of the essential characteristics of retractable type fall arresters. This article presents the requirements for locking of the devices. A previously used locking test method and its disadvantages are discussed. The article suggests an improved test method and test equipment. Measurement of the test mass acceleration is the most important improvement introduced into the test method. The article shows laboratory tests used to verify the method, which turned out to be a valuable source of information concerning the performance of retractable type fall arresters.     

Attracting retirees to apply: desired organizational characteristics of bridge employment

This research examined the impact of three organizational policies on applicant attraction of 120 older workers with an interest in bridge employment (i.e., work after formal retirement). Using a mock newspaper ad to manipulate policies, scheduling flexibility, and a targeted equal employment opportunity (EEO) statement positively influenced older workers' attraction to the organization, while opportunities to transfer knowledge had little impact. A significant and positive three‐way interaction suggested that older workers are sensitive to the strength of the overall message such that the effects of all three policies when seen together were greater than the sum of their individual effects. Copyright © 2005 John Wiley & Sons, Ltd.     

Metals distribution and interactions in tissues of shrews (Sorex spp.) from copper- and zinc-contaminated areas in Poland

To assess the risk from heavy metal accumulation to insectivorous species exposed to different pollutants, shrews [Sorex araneus (Linnaeus 1758) and Sorex minutus (Linnaeus 1766)] were collected in the Olkuski Ore Region (OOR; a Zn and Cd smelter area), Legnicko-G?ogowski Copper Mine Region (LGCR; a copper ore-mining area), and Bia?owieza Forest (BF; a control area). A few sites were chosen in each region and a total of 57 animals were collected from them. The liver and kidneys were dissected from the animals, dried, and digested in a 4:1 mixture of HNO3 (nitric acid) and HClO4 (perchloric acid). Cadmium, lead, zinc, copper, and iron were determined in the samples by flame or flameless atomic absorption spectrometry. The interactions between toxic and essential metals were calculated for each tissue. The data showed that accumulation of metals by insectivores is high; shrews accumulated much higher amounts of cadmium and lead than bank voles, studied by other researchers, from the same areas. The expected high tissue accumulation of copper at LGCR and zinc at OOR was not seen, but the levels of both elements were higher in the tissues of shrews from OOR than from LGCR. The lowest copper concentrations were in the tissues of shrews from BF. The highest cadmium and lead concentrations were found in the tissues of shrews from OOR. Some significant correlations were found between the tissue concentrations of xenobiotic and essential metals (e.g., between cadmium and zinc and between lead and iron).     

Knowledge and Power: A Critique of an International Relief Operation

Exploring an alternative way to approach famine relief interventions, this paper draws on the work of French philosopher Michel Foucault and David Keen's recent work on south-west Sudan. It suggests that different discourses on 'famine' can lead to the dominance of certain kinds of institutional practices, and the prioritisation of special kinds of knowledge, at the expense of other modes of understanding and action. Using the case of the relief operation to Tigrayan refugees in eastern Sudan in 1984/5, the paper examines the specific ways in which 'power' was elaborated in the midst of the operation, and the manner in which institutional practices — designed to save as many lives as possible — influenced the reaction of international agencies to the spontaneous repatriation of the Tigrayans back to Ethiopia.     

Pure oxygen-enhanced biodegradation for contaminated groundwater

On-site oxygen generation was chosen as the most effective and efficient source of pure oxygen for enhancing biodegradation at a hydrocarbon-contaminated oil and gas well site in northern Michigan. Contaminants include benzene, toluene, ethylbenzene, and xylenes released through natural gas dehydration practices that were halted in 1985. Free product and contaminated soil were completely removed from the source area in spring 1989, leaving only the groundwater plume for further remediation. This article discusses the project's two phases—a purge and treat system and the pure-oxygen bioremediation system—each costing $75,000. It also details the combined system's technical elements (including purge and monitoring wells, oxygen generator, and drainfield), and cleanup results (including how pure oxygen has helped destroy contaminants, not merely move them to other media).     

RIVER PHOSPHORUS DYNAMICS AND RESERVOIR EUTROPHICATION POTENTIAL1

ABSTRACT: Sediments from the Pompton and Passaic Rivers at Two Bridges were analyzed for potentially available phosphorus fractions and total phosphorus (TP). Water samples from the same sites were analyzed for dissolved phosphorus, TP, suspended solids (SS), and volatile SS. Significant negative correlations between river TP concentrations and flow were observed. However, storm flows resulted in increases in TP and SS concentrations and flux (loadings). Most of the increase in river P loading at high flow was in the dissolved fraction, suggesting that the sediments may be a large source of dissolved P. Concentrations of potentially available P in the sediments ranged from 140 to 1310 times the TP concentration in the overlying water. According to a modified Vollenweider model, current P concentrations in the Pompton and Passaic Rivers will result in excessive P loading in the Wanaque Reservoir if even small volumes of river water are pumped to the reservoir through the recently completed Wanaque South pipeline. Reductions in sewage treatment plant effluent P concentrations alone will not produce sufficient decreases in river phosphorus concentrations to avoid this predicted overloading and eutrophication.     

Kinetics of Aerobic Polymer Degradation in Soil by Means of the ASTM D 5988-96 Standard Method

The standard test method ASTM D 5988-96 for determining the degree and rate of aerobic biodegradation of plastic materials in contact with soil was applied to poly(3-hydroxybutyrate) and poly(-caprolactone). The method proved to be reliable and supplied reproducible measurements of CO₂ production, provided potassium (instead of barium) hydroxide was used as a trapping solution. The trends of CO₂ evolution, as a function of time, observed for the degradation of polymer powders in soil are similar to those predicted by simple first order kinetics in solution. The experimental data are described by a Michaelis–Menten type model, which accounts for the heterogeneity of the polymer-soil system. The kinetic equation deduced predicts the degradation rate to the proportional to the exposed polymer surface area.     

Effects of cadmium and zinc on larval growth and survival in the ground beetle,Pterostichus oblongopunctatus

Carabid beetles, like Pterostichus oblongopunctatus, living in metal contaminated areas may be exposed to elevated levels of metals within their diets. However, when compared to other second order consumers, they have one of the lowest observed levels of metals, indicating methods of detoxification to deal with such toxicants. In this study, we investigated if chronic, multigenerational exposure to metals leads to resistance to toxic metal concentrations, and if so, what are the costs associated with them. Adult organisms were collected from two sites, a polluted and a reference site near Olkusz, in southern Poland. These adults were immediately mated, and eggs were collected twice weekly to assess the effects in the larvae of the F(1) generation. Larvae were randomly exposed to one of four artificial mediums: control, 50 mg kg(-1) Cd, 500 mg kg(-1) Zn, and a combined treatment of 50 mg kg(-1) Cd and 500 mg kg(-1) Zn to investigate possible interactions. Individuals were sacrificed at 10, 30, and 40 days. Although metals were not accumulated in larvae (p>0.05), larvae fed the Cd or the Zn treatment grew significantly slower, and had the lowest survival rate (p<0.05) in respect to control. Out of metal treated animals, those on the combined treatment of CdZn grew the quickest and had the highest observed survival (p<0.05). Although previous studies have demonstrated changes in adult population parameters under chronic, multigeneration exposure to toxic metal concentrations, our study did not reveal any changes in the larval stage.     

An assessment of the toxicity of pyridinium chlorides and their biodegradation intermediates

Toxicity investigations were conducted for four pyridinium chlorides belonging to cationic surface-active substances (CSAS), which differed from each other in the numbers of methyl groups (CH(3)) in pyridinium ring.The crustacean Daphnia magna, the fish Lebistes reticulatus and the alga Scenedesmus quadricauda were chosen as biotests. Toxicity of examined preparations appeared to be very high but did not depend on their chemical structure. S. quadricauda was the most sensitive organism. Toxicity of intermediate products obtained in biological oxidation process was also examined. Biodegradation was conducted according to the "river water test". It was found that only partial degradation took place while pyridinium chlorides constituted main energy and carbon source. Presence of biodegradation intermediate products was shown on the basis of 1H NMR analysis. Intermediates were not toxic to any biotests.     

Public support for ecosystem restoration in the Hudson River Valley,USA

We applied the Theory of Planned Behavior to help understand the relationships between environmental beliefs, support for ecosystem restoration actions, and willingness to pay (WTP) for restoration and protection goals in the Hudson River estuary, New York State, USA. We conducted a mail survey with 3,000 randomly-chosen local residents of the Hudson River estuary in the fall of 1999. As hypothesized, the broad ecosystem restoration goals of the Hudson River Estuary Action Plan were more strongly supported than the corresponding specific implementation actions. We found that beliefs and past behavior were better explanatory variables than sociodemographic characteristics for explaining people's support for ecosystem restoration actions and WTP for restoration and protection goals. Because ecosystem restoration goals appear to be more generally acceptable than specific restoration actions, proponents of restoration programs should not become complacent about the need for active public outreach and involvement even if initial restoration program discussions have been low in controversy. Efforts to assess and foster support for ecosystem restoration should be targeted toward audiences identified on the basis of beliefs and past behaviors rather than on sociodemographic characteristics.